The MIMO technology has been widely applied in the current high-speed communication and next-generation wireless communication systems. Currently, the MIMO is an important physical-layer part of the latest communication standard. If Channel State Information (CSI) needs to be fed back, the MIMO technology is called a closed-loop technology; otherwise, the MIMO technology is called an open-loop technology. Generally, by using the CSI fed back, the closed-loop technology is better than the open-loop technology in that the former supports precoding to accomplish better link reliability, higher system throughput, and simpler receiver structure.
However, the performance of a closed-loop system is vulnerable to errors such as feedback delay, user mobility, and CSI quantization error. The current research on the closed-loop system is focused on the attempts to design an effective quantization algorithm under finite feedback conditions, specify how the CSI quantization errors affect the downlink throughput, so as to obtain various codeword-based precoding algorithms. In the process of implementing the present invention, the inventor finds at least the following defects in the prior art:
Most multi-user MIMO downlink scheduling algorithms in the prior art take only the CSI of the user into account, and cannot reflect mobility properly, and the existing MIMO schemes do not support intermixing of open-loop coding modes and closed-loop coding modes.